A 16-year-old suspect was charged with murder and strangulation in the death of an 8-year-old Virginia boy who was trying to defend his sister during a sexual assault, police said Saturday.

Richmond police are not identifying the suspect because of his age.
He was taken into custody after the attack was reported at 6:30 p.m. Thursday, but police waited to charge him while he was being medically evaluated.
The victims, Martin Cobb and his 12-year-old sister, were playing on train tracks behind their familyâ€™s home when the suspect approached them, police said.

Family told NBC affiliate WWBT that Martin was trying to defend his sister when he was fatally struck, possibly with a brick. He died at the scene, while his sister was taken to the hospital, where she was still recovering Friday.
Police declined to detail the attack or the severity of the girlâ€™s injuries.